Divergent Syntheses of (<i>Z</i>)-3-Alkylideneisobenzofuran-1(3<i>H</i>)-ones and 1<i>H</i>-Isochromen-1-ones by Copper-Catalyzed Cycloisomerization of 2-Alkynylbenzoic Acids in Ionic Liquids
作者:Raffaella Mancuso、Christian S. Pomelli、Piera Chiappetta、Katia F. Gioia、Asif Maner、Nadia Marino、Lucia Veltri、Cinzia Chiappe、Bartolo Gabriele
DOI:10.1021/acs.joc.8b00923
日期:2018.6.15
The cycloisomerization of readily available 2-alkynylbenzoic acids 1 in ionic liquids (ILs) as recyclable reaction media has been studied under the catalytic action of CuCl2. With substrates bearing an aryl group on the triple bond, a mixture of (Z)-3-alkylideneisobenzofuran-1(3H)-ones (from 5-exo-dig cyclization) and 1H-isochromen-1-ones (from 6-endo-dig cyclization) was observed in 1-ethyl-3-methylimidazolium
在CuCl 2的催化作用下,已经研究了易得的2-炔基苯甲酸1在离子液体(ILs)中作为可循环反应介质的环异构化。在具有在三键上带有芳基的底物的情况下,(Z)-3-亚烷基亚异苯并呋喃-1(3 H)-ones(来自5 exo - dig环化反应)和1 H -isochromen-1-ones(来自6 -内型-挖环化)的1-乙基-3-甲基咪唑鎓乙基硫酸盐(EmimEtSO观察到4),同时将反应原来是仅朝向使用异苯并呋喃酮的形成选择性ñ乙基N-甲基吗啉二氰胺[Mor 1,2 N(CN)2 ]作为溶剂。当在EmimEtSO 4或Mor 1,2 N(CN)2中使用带有末端三键的底物时,也有选择地获得了5元产物。另一方面,在EmimEtSO 4中,三键上带有烷基或烯基的2-炔基苯甲酸选择性地导致1 H -isochromen-1- one ,而在Mor 1中观察到区域异构混合物的形成。2 N(CN)2。